Footwear with improved upper

ABSTRACT

A boot including a sole assembly and an upper, the boot extending lengthwise from a rear end to a front end, widthwise between a lateral side and a medial side, and heightwise from the sole assembly up to an upper end, the boot including a first envelope that extends along a lower portion and an upper portion. For at least one of the lateral side and medial side, the first envelope includes a front lower flap, a rear lower flap, as well as a rear upper flap, the front lower flap partially extending along the rear lower flap, and the rear upper flap partially extending along the rear lower flap, the front lower flap and rear upper flap extending along the same surface of the rear lower flap.

CROSS-REFERENCE TO RELATED APPLICATION

The instant application is based upon the French priority Patent Application No. 09.06051, filed Dec. 15, 2009, the disclosure of which is hereby incorporated by reference thereto, and the priority of which is hereby claimed under 35 U.S.C. §119.

BACKGROUND

1. Field of the Invention

The invention refers to footwear, in particular a sports boot, and more particularly a boot adapted to be retained on a sport apparatus such as a snowboard or other gliding board.

2. Background Information

Boots of the aforementioned type can be used in fields such as snowboarding, skiing, snowshoeing, roller skating, but also walking and hiking, and the like.

For certain disciplines, it is advantageous to have a flexible boot. In snowboarding, for example, a flexible boot makes it easier to walk, execute acrobatic maneuvers, and to apply and receive forces to and from the board while being supported by and operating the board.

A snowboard boot according to the prior art is illustrated with reference to FIGS. 1 and 2, which are part of an annexed drawing shown in detail hereinafter.

According to FIG. 1, the boot 1 includes a sole assembly 2 and an upper 3. The upper 3 includes a first envelope 4, or outer envelope, which extends along a lower portion 5 and an upper portion 6 of the boot. The lower portion 5 is adapted to cover the foot of a user, whereas the upper portion 6 is adapted to cover the ankle and a portion of the lower leg. As shown more clearly in the cross-sectional view of FIG. 2, the boot 1 also includes an inner envelope 7, or slipper. The use of the slipper is not systematic, or mandatory, as it is not included in certain footwear.

During use, i.e., when operating the board, the user frequently bends and then extends his/her legs. During bending, the upper portion 6 is inclined forward towards the lower portion 5. Consequently, the outer envelope 4 deforms transversely at the midpoint 8 between the lower and upper portions. The deformation temporarily creates transverse deformations 9, 10, or bulges, which disappear when the boot 1 reassumes its natural, non-biased, shape. These bulges 9, 10 cause certain problems.

Indeed, in the situation of the boot 1 being retained on a sports apparatus, such as a snowboard or other gliding board, by means of the straps of a strap-in binding, one of straps typically encloses the wearer's instep and the instep area of the boot. In such a case, the strap extends along the midpoint 8. The strap, then, covers the bulges 9, 10. However, the strap, although flexible, is inextensible. Consequently, the bulges 9, 10 are compressed on the wearer's foot through the thickness of the upper 3. The bulges partially tend to project inward of the boot 1. As a consequence, rigid areas of the upper, defined by the bulges, press against the foot. This phenomenon creates sources of pain and can cause injuries, which generally occur in cases of extreme use, i.e., involving an acrobatic or an at least a demanding sports activity. Also, the rigid areas, or hard spots, on the upper can hamper the operation of the board, because the forward bending of the upper is hindered. This results, for example, in unnecessary fatigue, inaccurate transmission of steering forces and the receipt of sensory information to the wearer, or waste of time in executing the movements, in particular for the forward bending.

When no strap encloses the instep, or when the strap is not tightened, the transverse cross section of the boot increases in the area of the midpoint 8, thereby resulting in insufficient transverse foot support, which also hinders the steering of the board.

SUMMARY

In view of the preceding, the invention seeks in particular to improve a flexible boot that includes a lower portion and an upper portion.

More specifically, the invention reduces, and can even completely eliminate, hindrance to the operation of a gliding or rolling board, for example, that results from difficulty in bending the upper. Thus, the invention facilitates the bending of the upper, in particular the forward bending, without modifying the general properties of the boot, with respect to foot support forces, for example, related to operating the board.

Further, the invention completely eliminates, or at least to substantially reduces the risk of injuries, such as those that can occur during extreme use. In other words, the invention expands the range of applications for the boot.

Still further, the invention improves the transverse support of the foot in the boot, in particular in the area of the midpoint between the lower portion and the upper portion.

To this end, the invention provides a boot including a sole assembly and an upper, the boot extending lengthwise from a rear end to a front end, widthwise between a lateral side and a medial side, and heightwise from the sole assembly up to an upper end, the boot including a first envelope that extends along a lower portion and an upper portion.

At at least one of the lateral and medial sides of the boot of the invention, the first envelope includes a front lower flap, a rear lower flap, as well as a rear upper flap, the front lower flap partially extending along the rear lower flap, and the rear upper flap partially extending along the rear lower flap, the front lower flap and rear upper flap extending along the same surface of the rear lower flap.

The juxtaposing of the rear lower flap and the front lower flap demarcates a front juxtaposition zone. Similarly, the juxtaposing of the rear lower flap and the rear upper flap demarcates a rear juxtaposition zone. In these two zones, the rear lower flap is either closer to or further spaced from the inside of the boot than the front lower and rear upper flaps.

Because the inside of the boot receives the foot, the front lower flap and rear upper flap can be said to be offset with respect to the rear lower flap, while being further outside or further inside of the first envelope. Therefore, a flexional deformation of the boot moves the front lower flap and rear upper flap along the same surface of the rear lower flap. A forward bending, which brings the upper end of the boot towards its front end, therefore results in bringing the front lower flap and rear upper flap relatively closer to one another. The rear lower flap is then not biased, or is only slightly biased, in the direction in which it is not compressed along a longitudinal direction of the boot. Consequently, the transverse cross section of the boot, in the area of the midpoint between the lower and upper portions, remains substantially constant. Practically, this means that no bulge is formed at the midpoint of the zones. If a linkage or strap encloses this midpoint, then the tightening of the boot remains constant in this area in spite of a bending of the boot.

Among the resulting advantages is a great bending freedom for the upper, whereby the operation of the board is slightly hindered, or is not hindered at all.

The boot also provides for the elimination, or at least a substantial reduction, in the risk of injury.

Generally speaking, the boot according to the invention is an improvement to the prior art, with a broader field of application.

BRIEF DESCRIPTION OF DRAWINGS

Other characteristics and advantages of the invention will be better understood from the description that follows, with reference to the annexed drawings partially illustrating the prior art, as well as two non-limiting embodiments of the invention, and in which:

FIG. 1 is a perspective front view of a boot according to the prior art;

FIG. 2 is a cross section along the line II-II of FIG. 1;

FIG. 3 is a perspective front view of a boot according to a first embodiment of the invention;

FIG. 4 is a lateral side view of the boot of FIG. 3 according to its natural, i.e., unbiased, configuration;

FIG. 5 is a medial side view of the boot of FIG. 3 according to its natural configuration;

FIG. 6 is a view similar to FIG. 4, in a case in which the boot is biased in forward bending;

FIG. 7 is a cross section along the line VII-VII of FIG. 6; and

FIG. 8 is similar to FIG. 4, for a second embodiment proposed for the invention.

DETAILED DESCRIPTION

The first embodiment described hereinafter relates more specifically to snowboard boots. However, the invention applies to other fields, such as those mentioned hereinabove.

The first embodiment is described below with reference to the illustrations in FIGS. 3 to 7.

As shown in FIG. 3, a snowboard boot 21 is adapted to receive the foot of the wearer, i.e., the foot of the rider.

In a known fashion, the boot 21 includes an outer sole assembly 22 and an upper 23. The boot 21 extends lengthwise from a rear end, or heel 24, to a front end, or tip 25. The boot 21 also extends widthwise, between a lateral side 26 and a medial side 27. Finally, the boot 21 extends heightwise, from the sole assembly 22 up to an upper end 28.

The boot 21 includes a first envelope 31, which demarcates the outer portion of the upper 23. The first envelope 31 includes a lower portion 32, adapted to cover the foot, as well as an upper portion 33, adapted to surround the ankle and a portion of the lower leg of the user. The envelope 31 is part of the upper 23 and, as such, demarcates the upper end 28. The envelope 31 is affixed to the sole assembly 22 by any means, such as an adhesive, i.e., glue or welding, or stitching, for example.

According to the invention, for at least one of the lateral 26 and medial 27 sides, the first envelope 31 includes a front lower flap 41, 51, a rear lower flap 42, 52, as well as a rear upper flap 43, 53. Each of the front lower flap and the rear lower flap comprises at least part of the lower portion 32 of the envelope, and the rear upper flap comprises at least part of the upper portion of the envelope. The front lower flap 41, 51 partially extends the rear lower flap 42, 52, and the rear upper flap 43, 53 partially extends the rear lower flap 42, 52. The front lower flap 41, 51 and rear upper flap 43, 53 extend along the same surface 45, 55 of the rear lower flap 42, 52. Alternatively, it can be said that the front lower flap and the rear upper flap extend along the same surface level along the rear lower flap, i.e., thickness-wise of the upper. That is, regardless of the construction of the rear lower flap, i.e., whether it is made in one or plural pieces, i.e., whether constituting a single continuous surface or comprising one or more joined surfaces, the rear upper flap and the front lower flap are both situated against, and partially cover, the same surface level of the rear lower flap. In the illustrated embodiment of FIGS. 3-7, the same surface level is that of the outer side of the rear lower flap, whereby the rear upper flap and the front lower flap overlap the rear lower flap.

In other words, the front lower flap 41, 51 and rear upper flap 43, 53 are opposite the same surface 45, 55 of the rear lower flap 42, 52, respectively. The surface 45, 55, however, is only partially traversed by the flaps; that is, a free zone 46, 56 remains between the front lower flap 41, 51 and rear upper flap 43, 53, respectively. Consequently, a flexional deformation of the boot 21 moves the front lower flap 41, 51 and rear upper flap 43, 53 along the same surface 45, 55 of the rear lower flap 42, 52, respectively. The front bending therefore causes the front lower flap 41, 51 and rear upper flap 43, 53 to come closer together. The bending temporarily increases the surface areas of the front and rear juxtaposition zones. Thus, each rear lower flap 42, 52 is not subject to compressive stresses along a longitudinal direction of the boot. Therefore, the transverse cross section of the boot remains substantially constant in the area of the rear lower flap(s) 42, 52. Consequently, the tightening of the boot, via an outer linkage, or strap (not shown), and acting in the area of the flexion crease, or of the instep, therefore in the area of the rear lower flap(s) 42, 52, allows the upper 3 to have great bending freedom.

Examples of strap-in snowboard bindings which can be used in binding a boot according to the invention to a snowboard, which include an instep strap, are disclosed in U.S. Pat. Nos. 6,679,516 and 6,773,020, the disclosures of which are hereby incorporated by reference thereto in their entireties.

The front lower flap 41, 51 is adapted here to partially cover the rear lower flap 42, 52, and the rear upper flap 43, 53 is adapted to partially cover the rear lower flap 42, 52. In other words, according to the first embodiment of the invention, the surface 45, 55 of the rear lower flap, in the area of which the front lower flap 41, 51 and rear upper flap 43, 53 engage, is an outer surface 45, 55. Consequently, the rear lower flap, in the front and rear juxtaposition zones, is closer to the inside of the boot than the front lower and rear upper flaps.

According to the first illustrated embodiment, the first envelope 31 is adapted to include three flaps 41, 42, 43 and 51, 52, 53, respectively, for each of the sides 26, 27. More precisely, as it appears in FIG. 4 for the lateral side 26, the first envelope 31 includes a lateral front lower flap 41, a lateral rear lower flap 42, as well as a lateral rear upper flap 43, the lateral front lower flap 41 partially covering the lateral rear lower flap 42, and the lateral rear upper flap 43 partially covering the lateral rear lower flap 42. In the same manner, according to FIG. 5 for the medial side 27, the first envelope 31 includes a medial front lower flap 51, a medial rear lower flap 52, as well as a medial rear upper flap 53, the medial front lower flap 51 partially covering the medial rear lower flap 52, and the medial rear upper flap 53 partially covering the medial rear lower flap 52. This arrangement provides the boot 21 with the same bending ability for each of the lateral 26 and medial 27 sides. Consequently, front bending is facilitated.

The arrangement of the various flaps 41 to 43 and 51 to 53 is selected with the purpose of obtaining two combined effects, first, easier bending of the upper 23, as mentioned hereinabove, and, second, precise and comfortable foot support.

With initial reference to the lateral side, according to FIG. 4, the front lower flap 41 has a fastening edge 61 opposite a free edge 62, the edges 61, 62 being connected by a rear edge 63 and by a front edge 64. The fastening edge 61 is affixed to the sole assembly 22, for example by means of an adhesive, such as glue or weld, and/or stitching. The free edge 62, as described further hereinafter, can be biased to reversibly tighten the upper 23, i.e., to selectively tighten or loosen the upper with respect to the wearer's foot.

The position of the connecting edges 63, 64 is referenced with respect to a transverse plane J of the boot 21, which is level with the frontal surface 59 of the upper portion 33. The plane J is tangent to the frontal surface 59, considered when the boot 21 has its natural shape, i.e., its non-biased shape. The frontal surface 59 is the subdivision of the portion 33 that is the closest to the tip 25.

According to the first embodiment proposed, the rear edge 63 of the lateral front lower flap 41 extends rearward of the transverse plane J, while remaining spaced apart from the heel 24. For example, the rear edge is rearward by an amount ranging between 1 and 50 millimeters (mm) with respect to the transverse plane J. In the same manner, the front edge 64 extends forward of the transverse plane J, while remaining spaced apart from the tip 25. For example, the front edge is forward by an amount ranging between 30 and 120 mm with respect to the transverse plane J. However, the distance between the front edge 64 and the tip 25 is equal to or greater than 40 mm. Consequently, the fastening edge 61 measures between 30 and 140 mm, a value between 60 and 110 mm yielding good results.

The rear lower flap 42 has a fastening edge 71 opposite a free edge 72, the edges 71, 72 being connected by a heel zone 73 and an upper edge 74 on the side of the heel 24, and by a front edge 75 on the side of the front lower flap 41. Here again, the fastening edge 71 is affixed to the sole assembly 22 in a manner described above with reference to fastening edge of the front lower flap 41. The free edge 72 can be biased to reversibly tighten the upper 23.

The position of the upper edge 74 is referenced with respect to the limit 78 between the lower portion 32 and the upper portion 33. This limit 78 is located in the area of the flexion crease of the foot. Thus, essentially, the distance that separates the sole assembly 22 from the upper edge 74, of the lateral rear lower flap, is substantially the same as the distance between the sole assembly 22 and the limit 78.

The heel zone 73 extends in the area of the heel 24. The lateral rear lower flap 42 and medial rear lower flap 52 are co-extensive, i.e., continuous, in the area of the zone 73. This provides continuity to the upper 23 in the area of the heel.

Finally, the front edge 75 of the lateral rear lower flap 42 extends to be located ahead of the rear edge 63 of the front lower flap 41. The front edge 75 is in the area of, or proximate, the transverse plane J, mentioned above, and can intersect the transverse plane J. The edge 75 can also be provided to be rearward or forward of the transverse plane J, insofar as it remains forward of the rear edge 63 of the flap 41.

The rear upper flap 43 has a rear zone 81 opposite a free edge 82, such rear zone and free edge being connected by a lower edge 83 and an upper edge 84. The rear zone 81 extends within the area of the back of the lower leg of the user. The lateral rear upper flap 43 and medial rear upper flap 53 are co-extensive, i.e., continuous, in the area of the zone 81. The free edge 82 can be biased to tighten the upper 23.

The lower edge 83 is closer to the sole assembly 22 than the upper edge 74 of the rear lower flap 42. For example, essentially, the distance that separates the sole assembly 22 from the lower edge 83 of the lateral rear upper flap is less than the distance between the sole assembly 22 and the limit 78.

The upper edge 84 is in the vicinity or in the area of the upper end 28 of the boot 21.

The arrangement of the lateral flaps 41, 42, 43 shown hereinabove provides the upper 23 with great bending freedom on the lateral side 26. The same is true for the medial side 27, as will be understood hereinafter with reference to FIG. 5.

Thus, by considering the medial side 27, the front lower flap 51 is shown to have a fastening edge 91 opposite a free edge 92, these edges 91, 92 being connected by a rear edge 93 and a front edge 94. The fastening edge 91 is affixed to the sole assembly 22 in a manner described above with reference to the lateral side. The free edge 62 can be biased to tighten the upper 23.

According to the first embodiment, the rear edge 93 of the medial front lower flap is rearward of the transverse plane J, while remaining spaced apart from the heel 24. For example, the rear edge extends to be rearward by a value ranging between 1 and 50 mm with respect to the transverse plane J. In the same manner, the front edge 94 is forward of the transverse plane J, while remaining spaced apart from the tip 25. For example, the front edge extends to be forward by a value ranging between 30 and 120 mm with respect to the transverse plane J. However, the distance between the front edge 94 and the tip 25 is equal to or greater than 40 mm. Consequently, the fastening edge 91 measures between 30 and 140 mm, a value between 60 and 110 mm yielding good results.

The rear lower flap 52 has a fastening edge 101 opposite a free edge 102, the edges 101, 102 being connected by a heel zone 103 and an upper edge 104 on the side of the heel 24, and by a front edge 105 on the side of the front lower flap 51. Here again, the fastening edge 101 is affixed to the sole assembly 22. The free edge 102 can be biased to reversibly tighten the upper 23.

Essentially, the distance that separates the sole assembly 22 from the upper edge 104 of the medial rear lower flap 52 is the same as the distance between the sole assembly 22 and the limit 78.

The heel zone 103 extends in the area of the heel 24. The lateral rear lower flap 42 and medial rear lower flap 52 are co-extensive, i.e., continuous, in the area of this zone 103. In fact, the heel zones 73 and 103 merge with one another. This provides the heel 24 with unity.

Finally, the front edge 105 of the medial rear lower flap is located forward of the rear edge 93 of the front lower flap 51. The front edge 105 is in the area of, or proximate, the transverse plane J and can intersect the transverse plane J. The edge 105 can also be rearward of or forward of the transverse plane J, insofar as it remains forward of the rear edge 93 of the flap 51.

The rear upper flap 53 has a rear zone 111 opposite a free edge 112, such rear zone and free edge being connected by a lower edge 113 and an upper edge 114. The rear zone 111 extends in the area of the back of the lower leg of the wearer. The lateral rear upper flap 43 and medial rear upper flap 53 are co-extensive, i.e., continuous, in the area of this zone 111. In fact, the rear zones 111 and 81 are continuous with respect to one another. This makes the structure of the upper 23 uniform in the back, above the heel 24. The free edge 112 can be biased to tighten the upper 23.

The lower edge 113 is closer to the sole assembly 22 than the upper edge 104 of the rear lower flap 52. For example, essentially, the distance that separates the sole assembly 22 from the lower edge 113, of the medial rear upper flap 53, is less than the distance between the sole assembly 22 and the limit 78.

The upper edge 114 is in the vicinity or in the area of the upper end 28 of the boot 21.

The arrangement of the medial flaps 51, 52, 53 shown hereinabove provides the upper 23 with great bending freedom on the medial side 27. Overall, the boot 21 is flexionally free on the two sides 26, 27. This facilitates the steering of the board.

The bending ability can be appreciated by comparing FIGS. 6 and 7 with FIGS. 4 and 2, respectively. In FIG. 6, the boot 21 is bent, or flexed, toward the front 25. The bending has caused the front lower flaps 41, 51 to slide on the rear lower flaps 42, 52, and the rear upper flaps 43, 53 to slide on these same rear lower flaps 42, 52. Of course, the front lower flaps 41, 51 and rear upper flaps 43, 53 move on the lateral side 26 or medial side 27, respectively, without ever touching one another. As shown in FIG. 7, the transverse cross section of the boot 21 is not modified, or is only very slightly modified by the bending in the area of the flexion crease. This means that in a transverse plane F that extends through the flexion crease, i.e., also through the limit 78, and which forms, with the sole assembly 22, an angle α ranging between 30° and 60°, the transverse cross section of the boot 21 is stable. Consequently, no bulge is formed transversely as was the case for the prior art in FIG. 2.

The transverse cross section, shown in FIG. 7, also corresponds to the boot in its natural non-biased state, as is the case in FIGS. 3, 4, and 5.

Whether the boot 21 is flexed or not, the rear lower flaps 42, 52 have a regular convex curve outside of the envelope 31. This improves comfort, as has been disclosed, but also facilitates the cooperation with the other flaps 41, 43, 51, 53.

To complete its structure, the first envelope 31 includes an inner lining 121. The inner lining extends through the area of all of the flaps 41, 42, 43, 51, 52, 53, as well as at the front, between the front lower flaps 41, 51 and in the area of the front end 25. The flaps can be partially affixed to the envelope 121, for example by means of an adhesive or stitching. The inner lining 121 improves the cohesion of the envelope 31 in the area of the flaps 41 to 43 and 51 to 53, and also forms the vamp of the boot 21, i.e., the front portion of the upper 23. The lining is structured so that the flaps remain free to move. Thus, the lining 121 is flexible.

Further regarding the completion of its structure, the first envelope 31 includes a tongue 122, which is positioned between the lateral flaps 41 to 43 and medial flaps 51 to 53.

Thus, the first envelope 31 includes six flaps 41 to 43, 51 to 53, an inner lining 121, and a tongue 122.

The boot 21 also includes a mechanism 125 for reversibly tightening the first envelope 31, which acts on the flaps as mentioned above. In a non-limiting manner the tightening mechanism 125 includes a front keeper 130, lateral keepers 131 to 136, medial keepers 141 to 146, a lace 147 that runs through the keepers, and a device 148 for reversibly blocking the lace.

More precisely, the front keeper 130 is located on the lining 121, close to the tongue 122. Then, on the lateral side 26, the front lower flap 41 has two keepers 131, 132, the rear lower flap 42 has one keeper 133, and the rear upper flap 43 has three keepers 134 to 136. In the same manner, on the medial side 27, the front lower flap 51 has two keepers 141, 142, the rear lower flap 52 has one keeper 143, and the rear upper flap 53 has three keepers 144 to 146.

The distribution of the keepers is identical on the two sides 26, 27. This makes the tightening of the first envelope uniform.

The blocking device 148 is not described in detail here, as it is well-known to those having ordinary skill in the art. Examples of a lace blocking device that can be used in a boot according to the invention are disclosed in U.S. Patent Application Publication Nos. 2006/01745516 and 2007/0169380, the disclosures of which are hereby incorporated by reference thereto in their entireties. Alternatively, it is possible to use a knot instead of the device 148.

In addition to the foregoing, as shown in FIG. 7, the boot 21 includes a second envelope 151, structured and arranged to be inserted within the first envelope 31. In fact, the envelope 151 is a slipper that improves comfort in the use of the boot 21. The use of a slipper is however not mandatory.

A second embodiment of a boot according to the invention is summarily shown hereinafter with reference to FIG. 8. Substantially the same reference numerals are used in FIG. 8 as used for the first embodiment, as the two embodiments differ only in terms of particular details of arrangement.

Thus, the second embodiment includes a boot 21, having a sole assembly 22 and upper 23. The first envelope 31 includes, for the lateral side 26 and medial side 27, respectively, a front lower flap 41, 51, a rear lower flap 42, 52, and a rear upper flap 43, 53. Here again, the front lower flap 41, 51 extends partially along the rear lower flap 42, 52, and the rear upper flap 43, 53 partially extends along the rear lower flap.

The second embodiment is specific in that the front lower flaps 41, 51 and rear upper flaps 43, 53 extend along the same inner surface 155 of the rear lower flap 42, 52, i.e., they underlap the inner surfaces of the respective rear lower flaps. In other words, each rear lower flap 42, 52 partially overlaps a front lower flap 41, 51, as well as a rear upper flap 43, 53. The boot according to the second embodiment brings about the same advantages as the boot according to the first embodiment.

In any case, the invention is embodied from materials and according to implementation techniques known to those of ordinary skill in the art.

The invention is not limited to the particular embodiments described hereinabove and illustrated in the drawing, and it includes all of the technical equivalents that are within the scope of the claims that follow.

In particular, although the first envelope 31 includes exactly six flaps in the embodiments shown, it is possible, on one side, to reduce the number of flaps down to two, or to increase the number of flaps up to four, for example.

In addition, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein. 

1. An article of footwear comprising: a sole assembly; an upper extending upwardly from the sole assembly; a length extending between a rear end and a front end; a width extending between a lateral side and a medial side; a height extending between the sole assembly and an upper end; the upper comprising an envelope demarcating an outer portion of the upper and comprising a lateral side and a medial side, said envelope comprising: a lower portion structured and arranged to cover at least a part of a foot of a wearer; and an upper portion extending upwardly from the lower portion; at least one of the lateral side and the medial side of the envelope comprising: a front lower flap comprising at least part of the lower portion of the envelope; a rear lower flap comprising at least part of the lower portion of the envelope; a rear upper flap comprising at least part of the upper portion of the envelope; the front lower flap and partially extending along the rear lower flap; the rear upper flap partially extending along the rear lower flap; the front lower flap and rear upper flap extending along an identical surface level of the rear lower flap.
 2. An article of footwear according to claim 1, wherein: the front lower flap partially overlaps the rear lower flap; the rear upper flap (43, 53) partially overlaps the rear lower flap.
 3. An article of footwear according to claim 1, wherein: the front lower flap partially underlaps the rear lower flap; the rear upper flap partially underlaps the rear lower flap.
 4. An article of footwear according to claim 1, wherein: on the lateral side the envelope includes a lateral front lower flap, a lateral rear lower flap, and a lateral rear upper flap; the lateral front lower flap partially covers a surface of the lateral rear lower flap, and the lateral rear upper flap partially covers a surface of the lateral rear lower flap.
 5. An article of footwear according to claim 1, wherein: on the medial side, the envelope includes a medial front lower flap, a medial rear lower flap, and a medial rear upper flap; the medial front lower flap partially covers a surface of the medial rear lower flap, and the medial rear upper flap partially covers a surface of the medial rear lower flap.
 6. An article of footwear according to claim 4, wherein: on the medial side, the envelope includes a medial front lower flap, a medial rear lower flap, and a medial rear upper flap; the medial front lower flap partially overlaps the medial rear lower flap, and the medial rear upper flap partially overlaps the medial rear lower flap.
 7. An article of footwear according to claim 6, wherein: the lateral front lower flap and the medial front lower flap have respective rear edges; the rear edge of the lateral front lower flap and the rear edge of the medial front lower flap extend rearward of a transverse plane level with a frontal surface of the upper portion.
 8. An article of footwear according to claim 6, wherein: the lateral rear lower flap and the medial rear lower flap have respective rear edges; the front edge of the lateral rear lower flap and the front edge of the medial rear lower flap are proximate a transverse plane level with a frontal surface of the upper portion.
 9. An article of footwear according to claim 6, wherein: the sole assembly is separated from the upper edge of the lateral rear lower flap by a distance equal to a distance separating the sole assembly and a limit between the lower portion and the upper portion of the envelope; the sole assembly is separated from the upper edge of the medial rear lower flap by a distance equal to a distance separating the sole assembly and the limit between the lower portion and the upper portion of the envelope.
 10. An article of footwear according to claim 9, wherein: the limit between the lower portion and the upper portion of the envelope is a transverse plane extending through a flexion crease in an instep area of the boot.
 11. An article of footwear according to claim 6, wherein: the sole assembly is separated from the lower edge of the lateral rear upper flap by a distance which is less than a distance separating the sole assembly and a limit between the lower portion and the upper portion of the envelope; the sole assembly is separated from the lower edge of the medial rear upper flap by a distance which is less than a distance separating the sole assembly and the limit between the lower portion and the upper portion of the envelope.
 12. An article of footwear according to claim 1, wherein: the upper includes an inner lining.
 13. An article of footwear according to claim 1, further comprising: a mechanism for reversibly tightening the envelope, which acts on the flaps.
 14. An article of footwear according to claim 1, further comprising: a mechanism for reversibly tightening the envelope, said mechanism comprising a plurality of lateral keepers, a plurality of medial keepers, and a lace extending through said lateral and medial keepers;
 15. An article of footwear according to claim 14, further comprising: a device for blocking the lace to maintain a tension in the lace.
 16. An article of footwear according to claim 6, wherein: the envelope includes exactly six flaps consisting of said lateral front lower flap, said medial front lower flap, said lateral rear lower flap, said medial ear lower flap, the lateral rear upper flap, and the medial rear upper flap. 